Howie seems to be back to normal this morning!! We ended up not taking any asprin. I called the 24-hour emergency vet that my vet says to call on his recorded message and they were no help - they said that they couldn't even say whether or not half of a baby asprin was Ok or not b/c of liability reasons! So me and the pup headed off to bed early and got under layers of blankets and just snuggled. He woke up a few times during the night, but nothing major. So, YAY!! He's back!
Thanks to everyone who helped me through my hysterics last night!